Progress of mid-infrared solid-state laser

Mid-infrared solid lasers, such as new type of Fe²⁺: ZnSe laser and Optical Parameter Oscillator(OPO) based on MgO: PPLN, ZnGeP₂ crystals, are reviewed in this paper. The scientific and technical problems of the mid-infrared solid laser are analyzed. The technical tendencies of mid-infrared solid laser are summarized. Based on the advantages of high efficiency, light weight and small volume, 3-5 μm mid-infrared solid-state laser sources have very important applications in the fields such as industry, medicine and military. The development of mid-infrared laser crystal with large bulk and high quality, and laser pump sources with high power and longer wavelength has become one of the developing trends for mid-infrared solid state laser in the future.